Key Concepts in Systematics and Biodiversity

Monophyletic group

A group that includes an ancestral species and ALL its descendants

Paraphyletic group

A group that includes an ancestral species and SOME, but not all, of its descendants

Polyphyletic group

A group that includes species derived from TWO OR MORE ancestral species

Synapomorphy

A shared derived character that appears in an ancestral species and is passed on to its descendants

Plesiomorphy

An ancestral character that appeared in an ancestor of the group being studied

Autapomorphy

A derived character unique to a particular species

Systematics

The study of biological diversity and evolutionary relationships among organisms

Taxonomy

The identification, naming, and classification of organisms

Binomial nomenclature

Naming system with genus and species (e.g., Homo sapiens); genus capitalized, species lowercase, both italicized

Community

An association of populations of different species that live and interact in the same place at the same time

Ecosystem

A biological community and its abiotic environment together

Biome

A large, relatively distinct terrestrial region with similar climate, soil, plants, and animals

Ecotone

The transition zone where two or more communities/biomes meet and integrate

Biogeography

The study of the geographic distribution of taxa

List the six biogeographic realms

Nearctic (North America), Neotropical (South America), Palearctic (Eurasia), Oriental (South Asia), Ethiopian (Africa), Australian

Three levels of biodiversity

Ecosystems, species, genes

What is LUCA?

Last Universal Common Ancestor; represents a phylogenetic event horizon, not a living organism

What experiment tested the Oparin-Haldane model?

Miller-Urey experiment, which produced amino acids under early Earth conditions

Background extinction vs. Mass extinction

Background: slow, gradual, common, diverse causes; Mass: fast, catastrophic, rare, indirect causes (volcanoes, asteroids)

Name the 'Big Five' mass extinctions

Ordovician, Devonian, Permian, Triassic, Cretaceous

Most severe mass extinction

Permian (252 MYA) - 96% of marine species extinct

Evidence for K-T extinction asteroid impact

Elevated levels of iridium in rocks worldwide; crater off Yucatan peninsula